Ludwig von Bertalanffy was an Austrian-born biologist who developed the idea of General Systems Theory, arguing that systems as a whole had properties and perhaps even laws, that were different from, and could not be reduced to, the properties and laws of their components. Others had recognized systems in various ways, often claiming that they are "more than the sum of their parts." Bertalanffy promoted the idea of "organicism," that systems of many kinds should be treated as organisms with multiple hierarchical levels. Like Ernst Mayr, Bertalanffy believed that holist biological models might be better models for systems than mechanistic reductionist models.

Bertalanffy was skeptical that Darwinian evolution, based on random chance variations, could explain all of biology.

From the standpoint of science... the history
of life does not appear to be the result of an accumulation of changes at random but subject to laws. This
does not imply mysterious controlling factors that
in an anthropomorphic way strive towards progressive
adaptation, fitness, or perfection. Rather there are principles of which we already know something at present,
and of which we can hope to learn more in the future.
Nature is a creative artist; but art is not accident or
arbitrariness, but the fulfilment of great laws,

(Problems of Life (1952), p.109)

Many nineteenth-century biologists were "vitalists," as was philosopher Henri Bergson with his élan vital. Like vitalism, Bertalanffy's organicism appears to incorporate some kind of non-physical and as yet undiscovered new force of nature.

Many scientists had known for decades before Bertalanffy that living systems somehow avoid the inevitable degradation suffered by physical systems, according to the second law of thermodynamics. Instead of approaching thermodynamic equilibrium (complete chaos and maximum entropy, living systems maintain themselves in a high state of order (or information). Earlier thinkers had called this a "dynamic equilibrium," but Bertalannfy called it "flow equilibrium," inventing the German word Fliessgleichgewicht," which was later translated into English as "steady state." In his 1932 book Theoretische Biologie, he described living systems as open systems that exchange matter and energy with the environment.

More important than the new terminology, Bertalanffy in 1940 described what was happening in a way made famous five years later by Erwin Schrödinger in his book What is Life?, namely that energy is not enough, it must be energy with low (or negative) entropy, or what Bertalanffy correctly called "free energy.".

Bertalanffy wrote:

In open systems we have not only production of entropy due to irreversible processes, but also import
of negative entropy. This is the case in the living organism which imports [consumes nutrients with] complex molecules that are high in free energy. Thus, living systems, maintaining themselves in a steady
state, can avoid the increase of entropy, and may even
develop towards states of increased order and organization.

(quoted in Uncommon Sense, The Life and Thought of Ludwig von Bertalanffy (1983), p.83)

In What is Life?, Schrödinger would say that "life feeds on negative entropy." Schrödinger described this as "order out of order" that distinguishes life from the "order out of chaos" exhibited by many complex physical systems studied today.

In terms of information philosophy, living systems are complex information-processing systems. They feed on other information-rich living systems. Living systems can be described as having a form or shape through which passes information-rich matter and energy with low entropy. The incoming matter and energy exit the living system as matter and energy, but now with high entropy. The information input is degraded in the process of maintaining the living system in its highly ordered information state.

Bertalanffy may have been the first biologist to fully appreciate this aspect of living systems. He also appreciated that the main difference between biological and physical systems was that the information content of biological systems means that they have a memory of the past or a "history," unlike most physical things.

The Historical Character of Life
Organisms are characterized by three principal attributes: organization, dynamic flow of processes, and
history. As has been stated before, "life" is not a
force or energy that, like electricity, gravity, heat, etc., is
inherent in, or can be imparted to, any natural body.
Rather it is limited to systems with a specific organization. Equally characteristic is the continuous flow and
the pattern of processes in the organism.

Konrad Lorenz said that properties that are a priori in the individual were a posteriori in the species

And finally,
every organism originates from others of the same kind,
and carries traits of the past, not only of its own individual existence but also of the history of the generations
which preceded it. We shall later try to define the living
organism in terms of its fundamental characteristics as a
"hierarchical order of systems in a steady state." This
definition, however, omits an important characteristic
about which we can say little in an exact way, but which
must not be completely lost from sight.

In physical systems events are, in general, determined
by the momentary conditions only. For example, for a
falling body it does not matter how it has arrived at its
momentary position, for a chemical reaction it does not
matter in what way the reacting compounds were produced. The past is, so to speak, effaced in physical
systems. In contrast to this, organisms appear to be
historical beings.